Infrared heating of filled glass bottles

ABSTRACT

A method of avoiding harmful effects of moisture condensing on the surface of filled beverage bottles by passing the bottles from the filling and capping machines through a zone where they are subjected to infrared heat in a general wavelength range between 1.5 microns and 3.5 microns to raise the liquid temperature in the capped bottles to room temperature without excessive heating of the glass bottles or the liquid closely adjacent to the bottle walls.

United States Patent w mflh m mnm "MP "w" wamn U a o e m nnWWdh. y aurr b AMVBGGAE 45680000 45667777 99999999 HHHHHHHH 00972246 11 8 8 2358 8429227 034456 6279990 w ,3 w 22333333 m v a C m. nm me SD- M D- cy mmd ww k 7 kk um3bmmm roe r HB-IFI-BB r 0. dc w N m e n 1 nm. e w i m P w l AFPA 1. 1.111 2 253 7 2247 FOREIGN PATENTS 584,168 1/1947 GreatBritain................ 34/4 Primary Examiner-Wayne A. Morse, Jr.

Attorney-Christel & Bean 53/21 FC. 53/1 ll RC, 53/127 ABSTRACT: A method of avoiding harmful effects of moisture condensing on the surface of filled beverage bottles 53/21 by passing the bottles from the filling and capping machines 1 1 1e7i34/4 214; 99/217 through a zone where they are subjected to infrared heat in a R t cited general wavelength range between 1.5 microns and 3.5 e microns to raise the liquid temperature in the capped bottles UNITED STATES PATENTS to room temperature without excessive heating of the glass 10/1936 Groven................ 34/4 X bottles or the liquid closely adjacent to the bottle walls.

B65b 63/08, 1365b 55/14, B67b 3/00 [54] INFRARED HEATING 0F FILLED GLASS BO'I'ILES 2 Claims, I Drawing Fig.

[5]] Int.

[50] Field of 2 PATENTEU JUHES nsn v mimic. HEQBERT c. SNYDEQ BY ATTORNEYS.

INFRARED HEATING OF FILLED GLASS BOTTLES BACKGROUND OF THE INVENTION The present invention relates to a method of preventing condensation of moisture on the surfaces of filled bottles between the time when they leave the filling and capping apparatus and the time when they are packed in cartons or the like.

When filled beverage bottles such as soda bottles leave the filling and capping machine the liquid contents of the bottles are commonly at a temperature substantially below room temperature. In some cases this is due to the fact that a cold fill is employed because CO is more fully and more rapidly absorbed in the liquid at temperatures around 30 to 35 F. In the case of noncarbonated beverages the filling is also usually cold because the liquid is under refrigeration up to the time of filling.

As the bottles leave the filling and capping machines moisture condenses on the exteriors of the bottles and the bottles are often immediately packed into cartons or cardboard wraps" and placed in storage. The moisture on the bottle surfaces then runs down onto the cartons or wraps," wetting them and causing them to become sodden and unsightly and lose strength.

Attempts to remedy this condition by drying off this condensed moisture by ordinary heating methods have proved impracticable. The glass walls of the bottles absorb heat rapidly and the liquid adjacent to the bottle walls is heated so rapidly that the contents boil and develop dangerous pressures before the main body of liquid in a container is heated sufficiently to prevent condensation on the bottle surface.

SUMMARY OF THE INVENTION According to the present invention the bottles leaving the filling and capping machines are subjected to infrared radiant heat within a selected wavelength band whereby the liquid contents of the bottles are heated so as to raise their temperature approximately 35 F. to bring such contents from approximately 35 F. to average room temperature.

Infrared emanations having a wavelength below 1.5 microns will not be absorbed in the water of the bottle contents. On the other hand, infrared emanations above 3.5 microns in wavelength will be absorbed in the glass of the containers and will therefore give the same unworkable results as ordinary convection heating. Therefore, the method of the present invention subjects the filled bottles to infrared heat having wavelengths chiefly between 1.5 microns and 3.5 microns at a sufficicnt intensity and for a sufficicnt time period to produce the desired temperature increase in the contents of the filled bottles.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE of the drawing is a somewhat schematic perspective view of a bottle conveyor line equipped with one form of infrared radiant heating apparatus suitable for the purposes of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the illustrated embodiment a row of filled and capped bottles containing a liquid such as soda, which have just emerged from the filling and capping machines, passes along a conveyor belt I supported on a conventional conveyor stand 11. The row of bottles passes between infrared heaters designated generally by the reference numerals l2 and 13 which are disposed at opposite sides of the path of the bottles.

While various sources of infrared heat radiation may be employed, gas-fired infrared generators manufactured and sold by the Combustion Division of Eclipse Fuel Engineering Com' pany represent one type of commercially available burner suitable for present purposes. As indicated in the drawing, each of the heaters 12 and 13 consists of a connected longitudinal row of infrared burners 14 which have at their facing surfaces ceramic burning grids 15.

The burners are connected so that fuel-air mixture flows through a series of burners and in the drawing the conduit for the fuel-air mixture is designated 17, the mixture being supplied from a fuel gas inlet 18 and an air blower 19. This fuel feeding and burning apparatus is known to those skilled in the combustion arts and need not be described in further detail herein.

The burners 14 shown schematically by way of example come in connectable sections which emit infrared heat at approximately l3,000 B.t.u.s per hour for each 6 -inch square burner section and which have face temperatures of approximately l,650 F.

The air-fuel supply apparatus illustrated in the drawing for the near side heater I3 is duplicated at the opposite side for the heater 12. Conventional pilot lights, not shown, will usually be provided.

As an approximate indication of the degree of the exposure to infrared heat required to raise quart soda bottles from 35 F. to 70 F., the following general specifications will serve as a guide:

If a single row of l-quart soda bottles is passing along conveyor I0 the burners 14 will preferably be arranged two high instead of the single burner height illustrated in the drawing. This will give a vertical burner face of 12 inches and the burners will preferably be spaced so that their faces are from one to 3 inches from the passing bottles. With 20 longitudinal feet of burner surface at each side of the conveyor; and at average conveyor speeds each bottle will be exposed to the infrared emanation of the burners for about 13 seconds.

Smaller bottles require less exposure for the same tempera ture increase and therefore the conveyor may run faster or less longitudinal burner length is required. Any fuel gas may be employed with the burners described above and in fact any source of infrared radiation which will approximate the degree or quantity of infrared radiation indicated above wherein the wavelengths of the emanation are predominantly between 1.5 and 3.5 microns.

Since the number and location of the burners varies with requirements of bottles of different sizes and with other variable conditions, the groups of connected burners 14 may be supported on adjustable floor stands such as one indicated by way of example at 20 in the drawing.

In further explanation of the novel heating of the liquid contents of bottles in accordance with the present invention, water has a strong absorption band between 2.6 and 2.9 microns, and carbon dioxide has an absorption band around 2.7 microns. Flint glass transmits approximately 70 percent of the radiation between 2 and 3 microns. The ceramic element infrared burners employed herein operating at 1,500 F. have a wavelength of maximum radiation of 2.66 microns. Ac cordingly, the infrared emanation directly heats the liquid in the bottle instead of depending upon heating the contents by conduction through the container wall as in prior heating methods.

In tests on l6-ounce bottles filled with water and others with soda and with the bottles approximately 1 inch from the burner surfaces the following heat-up rates were observed: Liquid: Rate Water F./see. 0.76 Lemon-lime soda do 1. 37 Cola -do Average do 1. 1 1

Averagenn u do 0.60 I The higher rate of heating for the soda is believed to be due to increased heat absorption because of the dissolved CO Since the minimum starting temperature of the bottle contents will not be below approximately 32 F. and the ambient temperature will not ordinarily be above about 80 F. the maximum required temperature increase of the bottle contents will be about 50 F. It may be assumed that a temperature difference between bottle contents and ambient temperature of less than about F. will cause no moisture condensation problem. From this it may be postulated that the degree of infrared radiation required to overcome the moisture condensation problem in the general range of conditions encountered will require imparting to the contents of each bottle from about 1 to about 3 B.t.u.s for each ounce of liquid contained in the individual bottles.

The foregoing procedure would be useless on metal cans since the metal is opaque to infrared radiation and heating of the liquid contents would only be due to heating of the metal of the can and conduction of such heat to the liquid. In such cases the liquid in contact with the can sidewalls is heated so rapidly that it boils violently prior to heating of the interior contents. Pressure buildups in such a procedure render this procedure useless in connection with metal cans.

lclaim:

l. A method of heating the contents of capped liquid-com taining glass bottles to raise the temperature of the bottle contents from substantially below to approximately ambient ternperature, to avoid condensation of moisture on the bottle surfaces, which comprises passing the bottles from filling and capping apparatus directly to infrared heaters which subject the contents of the bottles to infrared radiation having wavelengths mainly between 1.5 and 3.5 microns which pass through the walls of the glass bottles with substantially no heating thereof but heat the liquid contained therein, the exposure of the bottles to infrared radiation being of an intensity and for a time period sufficient to impart to the bottle contents from about l to about 3 B.t.u.s per ounce of bottle contents.

2. In combination with apparatus for filling glass containers and capping the same, a conveyor for transporting a row of filled and capped glass containers therefrom, infrared heatradiating devices at opposite sides of said conveyor for raising the temperature of the bottle contents from substantially below to approximately ambient temperature, said infrared devices being directed toward said row of containers to sub ject the same to infrared rays predominantly in a wave length range from 1.5 to 3.5 microns which pass through the walls of the glass bottles with substantially no heating thereof but heat the liquid contained therein, the size and spacing of said infrared heat-radiating devices from the bottles and the speed of said conveyor being such as to impart to the bottle contents from about l to about 3 B.t.u.s per ounce of bottle contents. 

1. A method of heating the contents of capped liquid-containing glass bottles to raise the temperature of the bottle contents from substantially below to approximately ambient temperature, to avoid condensation of moisture on the bottle surfaces, which comprises passing the bottles from filling and capping apparatus directly to infrared heaters which subject the contents of the bottles to infrared radiation having wavelengths mainly between 1.5 and 3.5 microns which pass through the walls of the glass bottles with substantially no heating thereof but heat the liquid contained therein, the exposure of the bottles to infrared radiation being of an intensity and for a time period sufficient to impart to the bottle contents from about 1 to about 3 B.t.u.''s per ounce of bottle contents.
 2. In combination with apparatus for filling glass containers and capping the same, a conveyor for transporting a row of filled and capped glass containers therefrom, infrared heat-radiating devices at opposite sides of said conveyor for raising the temperature of the bottle contents from substantially below to approximately ambient temperature, said infrared devices being directed toward said row of containers to subject the same to infrared rays predominantly in a wave length range from 1.5 to 3.5 microns which pass through the walls of the glass bottles with substantially no heating thereof but heat the liquid contained therein, the size and spacing of said infrared heat-radiating devices from the bottles and the speed of said conveyor being such as to impart to the bottle contents from about 1 to about 3 B.t.u.''s per ounce of bottle contents. 